# Copyright (c) 2020, Adrian Dusa
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, in whole or in part, are permitted provided that the
# following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * The names of its contributors may NOT be used to endorse or promote products
#       derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL ADRIAN DUSA BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

`checkZone` <-
function(from, zones, checkz, nofsets, ib, ellipse) {
    fromz <- ib[ib$s == nofsets & ib$v == as.numeric(ellipse) & ib$i == from, ]
    toz <- ib[ib$s == nofsets & ib$v == as.numeric(ellipse) & ib$i %in% zones[!checkz], ]
    toz <- toz[toz$b %in% fromz$b, , drop = FALSE]
    if (nrow(toz) > 0) {
        zs <- sort(unique(toz$i))
        checkz[as.character(zs)] <- TRUE
        for (i in zs) {
            checkz <- checkz | Recall(i, zones, checkz, nofsets, ib, ellipse)
        }
    }
    return(checkz)
}
